Highly-sensitive and quantitative detection of a minute amount of a detection target substance such as protein and/or DNA in laboratory tests or the like makes it possible to perform treatment while quickly determining the patient's condition. For this reason, the analysis method and analysis device which can highly-sensitively and quantitatively detect a minute amount of a detection target substance have been in demand.
Surface plasmon-field enhanced fluorescence spectroscopy (hereinafter abbreviated as “SPFS”) is known as a method which can detect a detection target substance with high sensitivity (see, for example, PTLs 1 and 2).
PTLs 1 and 2 disclose an analysis method and analysis device that utilize SPFS. In the analysis method and analysis device, a sensor chip is used, which includes: a prism composed of a dielectric; a metal film formed on one surface of the prism; and a capturing body (e.g., antibody) fixed onto the metal film. When a sample containing a detection target substance is provided on the metal film, the detection target substance is captured by the capturing body (primary reaction). The captured detection target substance is then labeled by a fluorescent material (secondary reaction). In this state, when the metal film is irradiated with excitation light through the prism at an angle where SPR occurs, localized-field light can be generated on the surface of the metal film. With this localized-field light, the fluorescent material used for labeling the captured detection target substance on the metal film is selectively excited, and the fluorescence emitted from the fluorescent material is observed. In the analysis device and analysis method, the fluorescence is detected to thereby detect the presence or amount of the detection target substance.
In such an analysis method and analysis device utilizing SPFS, an excitation-light cut filter that blocks excitation light but allows fluorescence to pass through the filter is provided before a light sensor that detects the fluorescence.